The main objective of this project is to determine the minimal chemical and structural properties of bacterial endotoxins necessary to elicit several biologic and immunologic responses. The purpose is to identify, by fractionation of different endotoxins and chemical, physical, and biological analyses of the individual fractions, the component(s) of the macromolecular complex responsible for the antitumor effects of some endotoxins. Techniques are being developed to assess the cellular nature of the immunomodulatory activities of different endotoxic materials.